Definitions Flashcards
Movement
an action by an organism or
part of an organism causing a change of
position or place
respiration
the chemical reactions in cells
that break down nutrient molecules and
release energy for metabolism
sensitivity
the ability to detect or
sense stimuli in the internal or external
environment and to make appropriate
responses
growth
a permanent increase in size and
dry mass by an increase in cell number or cell
size or both
reproduction
the processes that make
more of the same kind of organism
excretion
removal from organisms of the waste products of metabolism toxic materials, and substances in excess of requirements
nutrition
taking in of materials for energy,
growth and development; plants require
light, carbon dioxide, water and ions; animals
need organic compounds and ions and
usually need water
species
a group of organisms that can
reproduce to produce fertile offspring
binomial system
an internationally agreed
system in which the scientific name of an
organism is made up of two parts showing the
genus and species
tissue
a group of cells with similar
structures, working together to perform a shared
function
organ
a structure made up of a group
of tissues, working together to perform specific
functions
organ system
a group of organs with
related functions, working together to perform
body functions
diffusion
the net movement of particles
from a region of their higher concentration to
a region of their lower concentration down
a concentration gradient, as a result of their
random movement
osmosis
the net movement of water
molecules from a region of higher water
potential (dilute solution) to a region of lower
water potential (concentrated solution), through
a partially permeable membrane
active transport
the movement of
particles through a cell membrane from a region
of lower concentration to a region of higher
concentration using energy from respiration
catalyst
a substance that
increases the rate of a chemical reaction and is
not changed by the reaction
enzymes
proteins that function as
biological catalysts
photosynthesis
the process by which
plants manufacture carbohydrates from raw
materials using energy from light
limiting factor
something
present in the environment in such short supply
that it restricts life processes
ingestion
the taking of substances, e.g.
food and drink, into the body through the mouth
mechanical digestion
the breakdown of
food into smaller pieces without chemical change
to the food molecules
chemical digestion
the breakdown of
large, insoluble molecules into small, soluble
molecules
absorption
the movement of small
food molecules and ions through the wall of the
intestine into the blood
assimilation
the movement of digested
food molecules into the cells of the body where
they are used, becoming part of the cells
egestion
the passing out of food that
has not been digested or absorbed, as faeces,
through the anus
transpiration
loss of water vapour
from plant leaves by evaporation of water at
the surfaces of the mesophyll cells followed by
diffusion of water vapour through the stomata
translocation
the movement of
sucrose and amino acids in phloem
pathogen
a disease-causing organism
transmissible disease
a disease in which
the pathogen can be passed from one host to
another
active immunity
defence against a
pathogen by antibody production in the body
aerobic respiration
the chemical
reactions in cells that use oxygen to break down
nutrient molecules to release energy
anaerobic respiration
the chemical
reactions in cells that break down nutrient
molecules to release energy without using
oxygen
